Controllable pitch propeller with hinging trailing edge



Jan. 22, 1963 L. H. IBLOUNT 3,074,488

CONTROLLABLE PITCH PROPELLER WITH HINGING TRAILING EDGE Filed May 1 0, 1961 25 Gi Z4. 29 l 26 u 7\\ INVENTOR.

F l G. 3 LUTHER H. BLOUNT BY flmw *Quu ATTORNEYS United States Patent 3,074,488, CUNTROLLABLE PITH PROPELLER WITH HINGEJG TRAILING EDGE Luther H. Blount, 459 Water St, Warren, RJ. Filed May 10, 1961, Ser. No. 109,028 Claims. (Cl. 170160.1)

This invention relates to a controllable pitch propeller particularly for marine use.

In the use of controllable pitch propellers, it is usual to provide a rotating hub with a solid blade rotatably mounted in the hub about an axis in a plane generally at right angles to the axis of the shaft about which the hub rotates.

One of the objects of this invention is to provide a blade having a small trailing portion which will increase its pitch to a greater extent than the main body portion of the blade as the main body portion of the blade is moved to increase its pitch in either direction.

Another object of the invention is to provide a blade which will assist the tendency of the blade to return from ahead or astern pitch position to neutral position or a position of aifording no thrust in the direction of the axis of the shaft.

Another object of this invention is to increase the lift or thrust effect of the blade to provide a more effective reverse thrust of the propeller.

Another object of the invention is to provide an arrangement where additional and better control may be had of the movement of the blade in its hub.

With these and other objects in view, the invention consists of certain novel features of construction as will be more fully described and particularly pointed out in the appended claims.

In the accompanying drawings:

h gIGURE l is a perspective view of the propeller and FIGURE 2 is a fragmental end view partly in section and partly broken away;

FIGURE 3 is a section on line 3-3 of FIGURE 2 illustrating in dot-dash lines varying positions that the trailing edge of the blade may have;

FIGURE 4 is a fragmental sectional view through the blade and looking down on top of a part of the hub illustrating the blade as swung to an angular position; and

FIGURE 5 is a fragmental sectional view showing the slide and the guideway therefor as at line 55 of FIG- URE 2.

In proceeding with this invention, I have divided the swingable blade of the controllable pitch propeller into a leading part and a trailing part and hinge these two together. A guide and linkage arrangement is then utilized so that as the leading part of the blade swings, the trailing part will swing in the same direction but to a greater extent, thus providing an increasingly concave driving face of the propeller blade as it is moved about its axis.

With reference to the drawings, designates the hub of the propeller comprising a main body part 11 and a cap 12. A plurality of blades, here shown as three, are identical and each is referred to as 14.

The body part of the hub is provided with three bosses 15, each of which is recessed as at 16 (FIGURE 2) to rotatably mount the stud 17 of the blade 14. To this stud there are attached means for rotating the stud and the blade about the axis of this stud 17 which axis is located in a plane at right angles to the axis of the shaft upon which the hub 10 is mounted. The axis of stud 17 is parallel to a radius of shaft in this plane but is offset from such radius.

Each blade 14 comprises a major leading part 18 and a minor part of considerably less area Which is referred ice to as the trailing part 19. These two parts are hinged together by interfitting eyes 20 and 21 through which a pintle pin 22 (see FIGURE 4) extends so as to hingeably relate the trailing part to the leading part in each blade 14 along an axis which is at an angle to the axis of the stud 17.

The trailing part of the blade carries an arm 23 which is fixed thereto and which is shown in FIGURES 1 and 2 and is curved to follow the contour of the hub, leaving only a sutficient space so that it may have the desired angular movement. This arm 23 extends inwardly from the trailing edge or part 19 of the blade toward the stud 17. The inner end portion of arm 23 carries a cylindrical stud 24 projecting toward the axis of the drive shaft, which stud enters a hole 28 in which it fits in a cylindrical member 29 which is slidable in the bore 30 of block 25 which in turn is movable toward and from the drive shaft in the recess 26. This provides a universal motion connection of this lever 23 to the block 25. A leaf spring 31 may hold the block above the bottom of the recess. The arm 23 is also faired as seen at 27 on its opposite sides outwardly to blend into the hub.

It will also be apparent that as the blade 14 swings from a position in line with the groove 26 to a position at an angle to this groove, one of which positions is shown in FIGURE 4, there will be a different swinging movement of the trailing part 19 because it is guided by a slide whose path will cause a different swinging movement than the movement of the leading portion 18 of the blade. Thus the movement of the trailing portion 19 will swing through a greater are or a greater amount than a leading portion 18 of the blade as movement of the leading position occurs, and it will also be understood that if the blade is swung about its axis of the stud 17 to the other side of the slot 26 for a relatively reverse pitch, this same action will occur only in the opposite direction in such instance.

It will be apparent that as the propeller rotates in a liquid medium, the pressure which is afforded by the trailing part of the blade will assist the tendency of the blade to return to a neutral position as the hub rotates so that all blades will be in alignment with the groove 26 which extends in a plane at right angles to the axis of the shaft of rotation of the hub, and it will also be apparent that this increase in concaveness effect will be especially effective to increase considerably the stern thrust when the blades are adjusted for reverse action.

I claim:

1. A controllable pitch propeller comprising a hub rotatable about a shaft axis, a plurality of blades each rotatably mounted about an axis in a plane substantially at right angles to the shaft axis, each blade having a major leading part and a minor trailing part hinged together and movable together about said blade axis, and means moving and regulating the trailing part about the axis of the hinge relative to the leading part and in the same direction of movement as the leading part of the blade as both parts of the blade are rotated on the blade axis comprising said hub carrying a guide with a slide movable along said guide and arranged to extend transverse to the direction of the axis about which the hub rotates and offset from the blade axis, and a link connecting said trailing part to said slide.

2. A controllable pitch propeller as in claim 1 wherein said guide is a groove in said hub and said slide is a block in said groove.

3. A controllable pitch propeller as in claim 1 wherein said guide is a groove in said hub and said slide is a block in said groove and said link is fixed to said trailing part and pivoted to said block.

4. A controllable pitch propeller comprising a hub rotatable about a shaft axis, a plurality of blades each rotatably mounted about an axis in a plane substantially at right angles to the shaft axis, each blade having a major leading part and a minor trailing part hinged together about an axis at an angle to the blade axis and movable together about said blade axis, means for moving the blade about its axis, and means moving and regulating the movement of the trailing part about the axis of the hinge relative to the leading part and in the same direction of movement as the leading part of the blade as both parts of the blade are rotated on the blade axis.

5. A controllable pitch propeller as in claim 4 wherein each blade axis is parallel to but olfset from a radius from the shaft axis.

References Cited in the file of this patent UNITED STATES PATENTS Ring Jan. 31, 1939 Gilibertv Dec. 3, 1940 Allan May 1, 1951 FOREIGN PATENTS France Aug. 19, 1922 Great Britain Jan. 15, 1958 Germany Jan. 16, 1958 

4. A CONTROLLABLE PITCH PROPELLER COMPRISING A HUB ROTATABLE ABOUT A SHAFT AXIS, A PLURALITY OF BLADES EACH ROTATABLY MOUNTED ABOUT AN AXIS IN A PLANE SUBSTANTIALLY AT RIGHT ANGLES TO THE SHAFT AXIS, EACH BLADE HAVING A MAJOR LEADING PART AND A MINOR TRAILING PART HINGED TOGETHER ABOUT AN AXIS AT AN ANGLE TO THE BLADE AXIS AND MOVABLE TOGETHER ABOUT SAID BLADE AXIS, MEANS FOR MOVING THE BLADE ABOUT ITS AXIS, AND MEANS MOVING AND REGULATING THE MOVEMENT OF THE TRAILING PART ABOUT THE AXIS OF THE HINGE RELATIVE TO THE LEADING PART AND IN THE SAME DIRECTION OF MOVEMENT AS THE LEADING PART OF THE BLADE AS BOTH PARTS OF THE BLADE ARE ROTATED ON THE BLADE AXIS. 